Remove extraneous files

[joelhans]

Fixes #29

As far as I can tell, this removes all the files that are not currently being published on GitBook. These are duplicates or artifacts of previous organization that isn't relevant any more, and

If you look at the URLs of the published docs, there are 3 folders in use:

• /main-stuff/...
• /help/...
• /welcome/...

Plus a few extra files in the root directory, like README.md and SUMMARY.md.

I feel 98.5% confident that merging this won't absolutely demolish what we already have published on GitBook, but it would be nice to test it out. I'm not entirely sure if that's possible. Maybe if we merge this into a branch that's not main, then GitBook would let us preview the published site?

I also don't know if this has any implications for any edits that are saved in GitBook but not merged. cc @seekanddefine

[joelhans]

TIL about fdupes, which very helpfully provides output like this:

fdupes ./ --recurse;                                                20:58:27
./athens-research-governance-and-operations/meetings/tools/README.md
./athens-research-governance-and-operations/meetings/tools.md

./building-athens-build-develop-contribute/contributing-design.md
./learning-at-athens-academy-education/contributing-design.md

./building-athens-build-develop-contribute/develop-athens/product-management.md
./building-athens-build-develop-contribute/contributing/develop-athens/product-management.md
./athens-research-governance-and-operations/develop-athens/product-management.md

./building-athens-build-develop-contribute/develop-athens/README.md
./athens-research-governance-and-operations/develop-athens/README.md

./building-athens-build-develop-contribute/develop-athens/athens-components-documentation.md
./building-athens-build-develop-contribute/contributing/develop-athens/athens-components-documentation.md
./athens-research-governance-and-operations/develop-athens/athens-components-documentation.md

./building-athens-build-develop-contribute/develop-athens/athens-block-parser-documentation.md
./building-athens-build-develop-contribute/contributing/develop-athens/athens-block-parser-documentation.md
./learning-at-athens-academy-education/clojure/athens-block-parser-documentation.md

./building-athens-build-develop-contribute/develop-athens/development/product-development.md
./building-athens-build-develop-contribute/develop-athens/product-development.md
./building-athens-build-develop-contribute/contributing/develop-athens/development/product-development.md
./athens-research-governance-and-operations/develop-athens/product-development.md

./building-athens-build-develop-contribute/develop-athens/development/README.md
./building-athens-build-develop-contribute/develop-athens/development.md
./building-athens-build-develop-contribute/contributing/develop-athens/development/README.md
./athens-research-governance-and-operations/develop-athens/development.md

./building-athens-build-develop-contribute/develop-athens/datascript-attribute-table.md
./building-athens-build-develop-contribute/contributing/develop-athens/datascript-attribute-table.md
./athens-research-governance-and-operations/develop-athens/datascript-attribute-table.md

./building-athens-build-develop-contribute/develop-athens/operations.md
./building-athens-build-develop-contribute/contributing/develop-athens/operations.md
./athens-research-governance-and-operations/develop-athens/operations.md

./building-athens-build-develop-contribute/develop-athens/architecture.md
./building-athens-build-develop-contribute/contributing/develop-athens/architecture.md
./athens-research-governance-and-operations/develop-athens/architecture.md

./building-athens-build-develop-contribute/contributing-documentation.md
./learning-at-athens-academy-education/contributing-documentation.md

Useful in finding additional duplicate files.